However, scientists and researchers do not know exactly how we are supposed to use it, and retrieve the data, to really benefit from this meaning. Perhaps animals use this meaning to hunt for prey, flee certain areas, or a variety of other possibilities.
To continue this type of study, Kirschvink tested individuals by sending a rotating magnetic field to the subject while measuring his brain waves. As a result, Kirschvink discovered that when this field is rotated counter-clockwise, neutrons react to the change in rotation within their brains, and we have seen a visible peak in their electrical activity. This means that there must be some kind of magnetic sense in humans.
A magnetic field in a Faraday cage
Previous work has already tried to highlight a magnetic sense in humans, but they were not reproducible. Those of Joe Kirshvink, however, are, he says. Last April, he presented his results at the Congress of the Royal Institute of Navigation in the United Kingdom. He states that “humans have functional magnetoreceptors”. This discovery is also described in the journal Science Magazine.
The study concerned 24 persons and was only the subject of a communication; it is not published in a peer-reviewed journal. The experiment, begun in 2014 with Joe Kirschvink himself, used a large Faraday cage, an aluminum box shielding the electromagnetic environment. The “guinea pigs” sit in the cage, in the dark, and are exposed to a pure magnetic field, uniform, without any other interference or stimulus. The participants wore sensors on the skull to perform an electroencephalogram, in order to monitor their brain activity. Researchers can change the orientation of the magnetic field.
During this study, different tests were carried out; in some, a magnetic field as strong as that of the Earth slowly rotated around the participants’ heads. When the magnetic field turned counterclockwise, the alpha waves of the participants dropped. Neurons seemed to respond to the magnetic field. In addition, the neural response occurred after a short delay (a few hundred milliseconds), suggesting an active brain response, according to the researcher. For now, the results stop there but the researcher promises that other laboratories, in Japan and New Zealand, will try to confirm its results.
While the idea of the influence of these fields on the living has long been reserved for dowsers, magnetizers and other followers of pseudo-sciences, science offers for the first time credibility, in the form of plausible biological mechanisms and undeniable behavioral observations.
She thus draws the outlines of a magnetic sense, certainly still full of mysteries, but which no longer belongs to the paranormal.
At first sight, however, everything pushes to doubt the existence of a sensory perception of magnetic forces. Invisible, inaudible and impalpable, without flavor or smell, these forces born of the whirlwind of molten metals that animate the heart of the Earth are revealed only in the presence of compasses or magnets. The lines of the terrestrial field which connect each point of the planet with its magnetic poles north and south have crossed each of our cells, they remain an oddity in which one believes, rather than a physical phenomenon which one perceives. Besides, if smell has a nose, and a view of the eye, what would be the organ of reception of a magnetic field?
How to explain the fact that we have no awareness of this information?
And what could it do for us?
So many enigmas that let us imagine why the magnetic field has become an ideal scientific guarantee for the most sulphurous ideas …
The road will have been long before the hypothesis of man’s ability to detect magnetic fields emerges. Even now widely accepted facts, such as the presence of a magnetic sense in most migratory species, have been very difficult to impose.
“At first, there was enormous skepticism, both among biologists and physicists,” says Kenneth Lohmann, a biologist at the University of North Carolina in Chapel Hill, USA.
Evoked at the beginning of the last century, the hypothesis of a magnetic sense in some migratory birds was only recognized by the scientific community from the 1960s. Thanks to the ingenious idea of German researchers Wolfgang Wiltschko and Friedrich Merkel. “They placed robins in carbon paper cages, so that the birds leave traces by scratching the side they wanted to fly to,” says Hervé Cadiou, a researcher at the University of Strasbourg. In the presence of a disturbed terrestrial magnetic field, birds tended to move in a different direction than they usually preferred. After application of an artificial field, such disorientations were subsequently observed in various migratory species – birds, fish, turtles, lobsters, and even ants.
Today, no one doubts the fact that many animals, to find their way in their long migratory journeys, use variations in the direction of the magnetic field lines they cross.
But man is not a migratory species. And millions of years of evolution separate him from the turtle. There was no reason to think that we would share with her, or any other species, the faculty of feeling the magnetic field. Except that the researchers have realized, in the last thirty years, that this “magnetoreception” is present in almost every branch of the tree of life!
Moles, flies, bacteria, plants … so many families of non-migratory species whose behavior has finally revealed that they were also magnetoresponsive! Even large mammals would be concerned.
From photos taken by satellite, the team of Hynek Burda, University of Duisburg-Essen (Germany), indeed observed in 2009 that cows and deer tend to line up parallel to the axis north-south, except near the high-voltage lines, which disturb the magnetic field around them. “We are analyzing data for other animals, and I can already tell you that magnetoresception is present in many other species,” says the researcher.
If bacteria, plants and even cows can feel the magnetic field … so why not the man?
Until recently, this idea was largely disregarded, particularly because of controversial studies on human behavior. In the 1970s and 1980s, British biologist Robin Baker, who was then teaching at Manchester University, had tested the ability of his students to identify the direction they were headed, in an unknown location and blindfolded. His results, published in the journal Science in 1980, made a lot of noise: the students would have shown a natural ability to be in space … except when a magnet was fixed on their forehead! But the excitement aroused by this discovery would quickly collapse, because none of the researchers who tried to reproduce the work of Baker did not find these results.
The hypothesis of the human capacity to feel the earth’s magnetic field came out strongly discredited. It was resuscitated by the discovery of molecules sensitive to the magnetic field in different species, including man.
A track opened in the early 1970s … by chance. At the time, “the microbiologist Richard Blakemore discovers that when he puts a pot of marine sediments near a magnetic stirrer, used to stir liquid solutions, he draws a whirlwind,” says Hervé Cadiou. The British researcher then remarks that this vortex is created by bacteria hidden in the sediments, able to orient themselves with respect to the magnetic field thanks to a very particular molecule: the magnetite … used to make the needles of the compasses!
This mineral with magnetic properties forms long chains that cling to cell membranes. In the manner of the needle of a compass, these chains are always oriented in the north-south axis, which mechanically forces the bacteria to do the same. “These bacteria, which live in very special environments, with low oxygen concentrations, are still swimming along the magnetic field lines, which allows them not to get lost,” says Damien Faivre of the Max Planck Institute. .
Thus, living beings are able to produce their own compasses!
Could this magnetite be the key to the magnetic sense in animals? To find out, the researchers have started to hunt down this precious mineral, at the heart of many cells, organs and species … A painstaking work, but paying: this molecular compass has been identified in several animals, in the cells of the mucosa smell of trout, in the upper part of pigeon beaks and … in the human brain! What give shape to a first hypothesis of a mechanism likely to be at work in us: each movement of the head would lead that of magnetite always oriented in the north-south axis – compared to the cells that contain it . These movements would mechanically cause the opening of channels in the cell membrane, which would allow the sending of chemical messages to nerve cells in direct contact with them.
But this has never been demonstrated in humans. And, for many researchers, magnetite could be, in our species, a mere cellular waste …
A SECOND RECEIVER IN THE RETINA
The discovery of a second mechanism will, however, finish convincing them. This mechanism is considered for the first time in the late 1990s with the discovery of cryptochrome, a light-sensitive molecule found in plants and in the retina of many animals, including humans.
By reacting with light, this molecule produces free radicals, electrically charged particles whose position of electrons relative to each other influences the chemical reactions that occur in the retina. Now, the position of these electrons depends itself on the direction of the magnetic field! Changes in the latter may therefore result in variations in activity in the retina. What to imagine a second form of magnetorception, which would for example by the appearance of different spots, more or less bright, within the visual field, according to the orientation of the gaze relative to the magnetic field lines
This hypothesis is reinforced by numerous observations, beginning with a 1993 study showing that robins are able to orient themselves in relation to the magnetic field only under blue and green lights, to which cryptochrome is specifically sensitive. Other results tending to implicate this mechanism have been found in many species, like the vinegar fly or the cress of the ladies, famous laboratory plant. One of these species is Homo sapiens … and the demonstration is up to the reluctance of the scientific community on the subject!
WHAT IMPACT ON OUR ORGANIZATION?
In 2011, the team of Thorsten Ritz, from the University of California, Irvine (USA), created mutant flies, devoid of cryptochrome, and therefore unable to orient in relation to a magnetic field. However, after the human cryptochrome gene was transferred to them, these flies returned to their magnetic sense. Proof that human cryptochrome is also able to detect the magnetic field!
A discovery that reinforces the conclusions of the studies conducted by Franz Thoss in the 2000s. This German researcher showed, by subjecting several people to a test of detection of light stimuli of increasing intensities, that the human eye more easily detected the light when the gaze was directed parallel to the magnetic field lines. The difference in sensitivity was sufficiently weak to explain that, outside of any experimental setting, no one has ever seen this incredible faculty!
Today, the indices are there, numerous and solid: the man has all the molecular tools and all the cellular circuits to capture the magnetic fields. When some species only exploit magnetite or cryptochrome, others, like humans, could benefit from the activity of these two receptors at the same time. It remains to be seen if this information is well taken into account by our brain, and how it could, without our being aware, affect the functioning of our body.
Some published but never replicated studies have reported differences in the electrical activity of the brain or in the rapid eye movements of sleeping persons, depending on the orientation in which they were lying. But more serious studies, conducted on large population samples, are still lacking. Perhaps recent discoveries will finally allow such projects to be launched.
The researchers remain very skeptical about man’s ability to deduce his orientation from the magnetic field, since no study, since Baker’s, has highlighted such a faculty. “If it really exists, I would not trust it to find my direction,” laughs Thorsten Ritz.
And these discoveries are far from providing a scientific explanation to the practices of dowsers and magnetizers or feng shui. But they should strengthen the debate on another subject the question of health risks related to electromagnetic waves from power lines.
HIGH VOLTAGE LINES: FINALLY JUSTIFIED FEARS?
If our body is able to feel the magnetic field … can electromagnetic waves disturb it?
For high voltage lines, which produce fairly intense fields – unlike wi-fi, laptops or relay antennas, the hypothesis of a human magnetic sense raises the question. It must be said that the answer is today far from clear …
Certainly, some studies suggest that living near high-voltage power lines could increase the risk of developing childhood leukemia. But all the health agencies around the world consider that the proofs remain insufficient to establish in a certain way their dangerousness.
The International Agency for Research on Cancer does not even classify them as “probable” carcinogens, but only as “possible”, just like coffee. Among their arguments: the absence of a biological mechanism that can explain deleterious effects.
In this context, the hypothesis of a magnetic sense in humans is therefore an interesting explanation.
Indeed, studies have suggested, to explain the potential effects of electromagnetic waves on human health, that they would disrupt our sleep / wake rhythm. However, the magnetic field is itself involved in the regulation of biological rhythms of magnetoreceptor species, as has been demonstrated, in particular, in the fly and the plant. The presence of a magnetic sense in humans could thus constitute a first solid track to finally shed light on this question.
Why would we have kept a sense that we obviously do not know how to use?
“Perhaps a long time ago, our ancestors used it to orient themselves, and since we have lost that capacity,” Franz Thoss suggests.
Another hypothesis: despite the presence in our body of all the tools to perceive the magnetic field, we never developed the means to integrate this information and use it for our orientation. This is already the case of plants, whose magnetic field influences growth. If they do not take advantage of this magnetic sense, they would still have preserved cryptochrome for its other essential functions – receiving light and regulating daily biological rhythms. Perhaps the magnetorception has been preserved in the same way in humans, despite its uselessness …
One of the major difficulties in clearing this case is that the influence of the earth’s magnetic field is very weak, so difficult to demonstrate.
“This has slowed progress,” regrets Margaret Ahmad, University Paris-VI. But the main brake is probably psychological. This field in which few teams dare to embark “still bears the stigma of popular imagery associated with mages and magnetisers,” says Hervé Cadiou, who recognizes that “many non rigorous studies have been conducted on this subject in the past, and have done a lot of damage to research. “
Thanks to the stubbornness of some researchers, an impressive path has been taken. Fifty years ago, the magnetic sense was only a fantasy.
Now, it is admitted today that this phenomenon, which for a long time has come under the domain of the strange, irrigates almost all the branches of the tree of life. And after all, that life is sensitive to the forces that cradle it, in all parts of the globe, since its appearance … is it really so strange?